#ifndef PID_v1_h
#define PID_v1_h
#define LIBRARY_VERSION	1.1.1

class PID {

public:

	//Constants used in some of the functions below
#define AUTOMATIC	1
#define MANUAL	0
#define DIRECT  0
#define REVERSE  0

	//commonly used functions **************************************************************************
	PID(long*, long*, long*, // * constructor.  links the PID to the Input, Output, and
			double, double, double, int); //   Setpoint.  Initial tuning parameters are also set here

	void SetMode(int Mode);   // * sets PID to either Manual (0) or Auto (non-0)

	bool Compute();             // * performs the PID calculation.  it should be
								//   called every time loop() cycles. ON/OFF and
								//   calculation frequency can be set using SetMode
								//   SetSampleTime respectively

	void SetOutputLimits(long, long); //clamps the output to a specific range. 0-255 by default, but
										  //it's likely the user will want to change this depending on
										  //the application

										  //available but not commonly used functions ********************************************************
	void SetTunings(double, double, // * While most users will set the tunings once in the
			double);   //   constructor, this function gives the user the option
					   //   of changing tunings during runtime for Adaptive control
	void SetControllerDirection(int);// * Sets the Direction, or "Action" of the controller. DIRECT
									 //   means the output will increase when error is positive. REVERSE
									 //   means the opposite.  it's very unlikely that this will be needed
									 //   once it is set in the constructor.
	void SetSampleTime(int); // * sets the frequency, in Milliseconds, with which
							 //   the PID calculation is performed.  default is 100

							 //Display functions ****************************************************************
	double GetKp();			// These functions query the pid for interal values.
	double GetKi();			//  they were created mainly for the pid front-end,
	double GetKd();			// where it's important to know what is actually
	int GetMode();						  //  inside the PID.
	int GetDirection();					  //

private:
	void Initialize();

	double dispKp;	// * we'll hold on to the tuning parameters in user-entered
	double dispKi;				//   format for display purposes
	double dispKd;				//

	double kp;                  // * (P)roportional Tuning Parameter
	double ki;                  // * (I)ntegral Tuning Parameter
	double kd;                  // * (D)erivative Tuning Parameter

	int controllerDirection;

	long *myInput; // * Pointers to the Input, Output, and Setpoint variables
	long *myOutput;  //   This creates a hard link between the variables and the
	long *mySetpoint; //   PID, freeing the user from having to constantly tell us
					  //   what these values are.  with pointers we'll just know.

	unsigned long lastTime;
	long ITerm, lastInput;

	unsigned long SampleTime;
	long outMin, outMax;
	bool inAuto;
};
#endif

